Lawn-trimmer.



-0. KARCHER.

LAWN TRIMMER.

APPLICATION PIL'BD 1,111.2, 1912.

orro KARCHER, or CANTON, omo,

LAWN-marianna.

Specification of Letters Patent. i Applicationled January 2, 1912. Serial No. $68,953.

To all whom z't may concern: I

Be it known that I, O'rro KARCHER, a citizen of the United States, residing at Canton,'in the county of Stark and State of h10, vhave invented certain -new and useful Improvements 1n Lawn-Trimmers, of

p which the following is a specification.

The invention relates to lawn mowers and more particularly to a clipping machine for trimming the grass around treesfand shrubbery, in the angles of buildings and fences,

and at other places not readily reached by the more ordlnary ltypes of lawn mowers;

and the object of the invention is to provide an eiticient machine of simple parts, constructed and arranged with the operating mechanism contained and shielded within a relatively short traction drum, so that the cuttirgg blades maybe presented directly to the work and passed freely alongside land beyond and around lateral obstructions withoutthe same coming in contact with the traction drum.

Other important features of the invention pertain to the construction and arrangement of the operating parts to effect an automatic pressure of` one cutting blade against the other when the machine is pushed forlWard in operation; together with special means for positively adjusting such pressure, all without the use of sprmgs Aor other uncertain or yielding means.

The objects. of the invention, thus xset forth in general terms, are attained by the mechanism, construction and .arrangement illustrated for a preferred embodiment thereof in the accompanying drawing, forming part hereof, in which- Figure 1 isa plan view of the lawn trimmer showing the handle broken away;Fig.

' 2, a plan section of the lawn trimmer on line 2--2, Fig. 3; and Fig. 3, an elevation section of the lawn trimmer on line 3 3, Figs. 1 and 2.

Similar numerals refer to similar parts throughout the drawing.

The traction drum 1 `is composed of two traction wheels 2 and 2a spaced apart and secured together by the axle 3, partsk of which may be formed on each wheel and joined by a suitable tongue andsocketcoupling as' 4 and the pin 5, as shown. Peripheral flanges 6 and 6a are provided on the inner sides of the Wheels, the edges of which flanges terminate in a series'of cusps 7 alternatelyy positioned in staggered relation with respect to each` other and together forming a tortuous circumferential cam slot between the-wheels in the roller; and the planes of t e apices of the cusps on the several wheels are so vspaced apart as to leave a free annular interval between them.

The frame of the machine-is composed* of a substantially.I O-shaped body portion 9 located within the traction drum and hav- -ing bearings 10 vformed on cach sidje mounted on journals 11 which are\provided 0n the axle adjacent to the inner side ofv each wheel; from which O-shaped body portion a shank 12 extends rearward through Patented sept. 3, 1912.

eriphery ofthe the annular interval, on which shank is formed or secured the handle 13; andl from which O-shaped body portion a shank`14 v extends forward through the free portion of the cam slot, on which forward shank 1s formed or secured the relatively fixed cutting blade 15 which is provided with tapered cutting teeth 16 on its forwardedge.

' The oscillating cutting blade 17 provided with tapered cutting teeth 18 on its forward edge rests flatwise on the upper slde of the iixed cutting blade, to which it is preferably connected by means of the pivot bolt 19 located in the rear middlepart of the blades, on which .pivot bolt the upper blade is adapted to oscillate so that the lateral edges of its teeth will shear against the lateral edges of the teeth of the fixed cutting blade.

The upright pivot post 20 is provided at the forward end of the O-shaped body portion of the frame, onpwhih post is pivoted the operating arm 21, the forward end of which arm abuts and is engaged with the -central part of the oscillating blade, `as 1n the U-shaped boss 22 thereon; and the rear end of the operating arm is provided with the roller 23 located and adapted to operate in the tortuous circumferentlal cam groove in the traction drum, whereby an 'oscillat ing movement is given tothe pivoted cutter blade by a rotation of the drum; The oper ating bar 21 is preferably loosely journaledon t e pivot post 20 to ermit a slight vertical oscillationv of the ar, and a fulerum is provided for the upper side of the bar preferably by means of the sleeve 24 ad- ]ustably secured on the upper end of the yivot post and thel 'Eulcrum arm 25 extending downward and forward from the sleeve with its end abutting the upper side of the operating arm intermediate its pivot and its forward end. .The-pivot post is preferabl made in the form of a bolt, as shown, an the ad'u'stment of the fulcrum arm is readily ma e by the nut 26 thereof.

-By this construction and arrangement, it is evident that the upward rotation of the cusps 7 at the rear side of the traction drum, when the machine is' being pushed forward, serves to force the roller and the'rear end of the o erating bar upward and the forward engi thereof downward to press centrally against the oscillating cutting blade and thereby to press the teeth thereof flatwise and throughout their entire length against the teeth of the fixed cutting blade; andl that this pressure isl pro ortioned u on the resistance encountered; y'the cuttlng teeth-and the greater power applied to the cam roller .tooscillate the same, so that the pressure of the teeth together will be more positive when the shearlng work to be performed is greater.- f

-I claim:-

1.`A lawntrimmer including a traction drum with an axle therein and lhaving a circumferential cam slot, a frame' in the "drum A-journaled on the axle and having shanks extending rearward and forwar through the cam slet a handle on-.the rear,-

wardv shank and a b ade fixed on the for- A ward shank external to the drum, an oscillatin blade ivoted on the upper side of the ed bla e, an `operating arm loosely .pivoted on the frame and having the forward end extended through the cam slot and engagedwith the pivoted blade with. a roller on-'the rear end of the arm in the camv 4slotvfor oscillating the ivoted blade, and

a fulcru'm connected wit the frame abutthe operating arm whereby the pivoted t. blllgie is pressed--flatwise against the. fixed,

blade whenthe'drumds rotated in forward 55 2. A lawn trimmer includin a tractionan axle therein and aving a cirumferential'cam slot between its edges, -a

frame-'1in ,thedrum journaled on' the 1x-Ie and having-Shanks extendin rearward and 'forward' t rou h the cam s ot, a handle 'onf the' rearward' s ank v'and a blade xed onithe frwardgshank ,external to the drum, an oscillating' blade secured on-the upper side of erat the fixed blade, an operating arm loosely pivoted on the frame and having the fer-v ward end` extended through the cam slot v and engaged with theupper blade with a roller on the rear end of the arm in the cam slot for oscillating .the upper blade, and a.

fulcrum connected with the frame abutting the operating armwhereby the oscillating blade is pressed ilatwise against the fixed blade when the drum is rotated in :forward direction.

3. A lawn trimmer I including a traction' drum with an axle therein and havin a f drum for. oscillating the pivoted blade,

Wherebythe ivoted blade isf pressed ilat- Wise against, t e xed blade when thedrum is rotated in forward direction.

4.l A lawn trimmer including' a traction drum with an axle therein and having a circumferential cam slot, a'frame journaled on the axle and having a blade xed thereon in front of the drum, an oscillating blade secured on the upper side of the xed blade,

an operatingarm loosely pivoted-on the frame and havin its forward end engaged with the upper lade with arolleron its rear end in the cam slot at the rear of the drum for oscillatin theupperblade," whereby the oscillating lade 1s pressed atwise against the fixed blade when the'drum isrotated in vforward direction.

5. A lawn trimmer including -a traction' drum with -an axlejtherein and having a circumferential cam slot, a frame journaled onthe axle and having a blade fixed thereto in front of-the. drum, an oscillating pivoted on the upper side of the fixe blade,

an .upright pivot ost on the frame, an op' erating arm loose y journaled on the post, 'andhavin its forward end engaged with the pivotev blade, there `being a roller on the rear end of the arm in the cam slot at therear of the drum for. oscillating the .pivoted blade, and an adjustable arm on the pivot post forming a fulcrunr for the'o pressed ilatfwise against the fixed blade whenV the'drum is rotated in forward'direction. 1

blade arm, whereby the pivoted blade 1s 6. A lawn trimmer including -a traction*v drum with an. axle therein -andha'vin al' circumferential slot,- aV frame journa ed' om the axle and havinga blade Yfixed thereon .the upper 'side' of' thqxed blade, an

upright 'pivot post on'the frame, an -opl 12B te infront of thejdrum,an oscillatingbladm ,Y

eratng arm loosely joulvn'aled on the post,` ann, whereby. the osoillating blade is pressed and hevnlits forward endl engaged withv atwise agamst the xed blade when the the upper ade, there being a. roller on the drum is rotated in forward direction.

mear end of the arm in the cam slotA at the OTTO KARCHER. l 5 rear of the drum for oscillating the upper Witnesses:

blade, and an adjustable arm'on the pivot v RUTHA. MILLER,

post forming a fulcrum for the operatingl FERD lJ. ZE'mLER. 

